In the prior art, such type of ribbon cassette is available, which includes a ribbon cassette case, the ribbon cassette case accommodates a printing tape for printing, a medium tape for providing printing medium and a carrier tape used as a carrier. The printing tape is discharged from a discharging port along a feeding path, and a printing part is disposed at the upstream of the discharging port is provided. The printing tape and the medium tape converge at the printing part, and printing information on the printing medium is thermally transferred onto the printing tape by a thermal transfer head of a printing device. Next, the printing tape and the carrier tape are adhered around the discharging port, and meanwhile are discharged from the ribbon cassette case. Then, the adhered printing tape and carrier tape are cut off at the position of cutting knife of label printing device to generate a label desired by a user.
However, for different applications, printing tapes with different widths are needed and, meanwhile the information corresponding to the printing tapes with different widths are stored in the printing device, and only when the information detected by the printing device is matched with the actual information of the ribbon cassette, will the printing device perform printing task, otherwise a printing error message will be prompted. The prior art, for example Chinese patent No. CN102481794A, discloses a strippable marking part which can be detachably installed on a ribbon cassette and information of different printing tape width is reflected by different strippable parts. This method can determine feature information of the ribbon cassette. However, it requires different marking parts for the information of different printing tape width. Therefore, the number of molds being used is increased and, thus, the total cost of the product is increased.
As disclosed in Chinese patent No. CN101850672A, a first indicator portion and a second indicator portion are used to determine the feature information of a ribbon cassette, and a combination of pore and non-pore portions provided by the first and second indicator portions reflects different feature information of the ribbon cassette. However, since the ribbon cassette is small as a whole, and the porous and non-porous parts matched with the printing device occupy the smaller space, in the case that the adjacent positions have pores, then the distance between centers of two pores is only slightly greater than the diameter of the pores, so that the diameter of the pores is only slightly greater than that of a determining column of the printing device. In the process of using the ribbon cassette, i.e., in the process of installing the ribbon cassette into the printing device, if there is a slight misplacement, it is highly possible that the printing device's determining column either cannot accurately enter the pore or cannot accurately contact the non-pore portion, which will lead that the printing device cannot accurately detect the feature information of the ribbon cassette, that is, printing task cannot be executed.
As disclosed in Chinese patent No. CN100429081C, a switching device used for determining width of a narrow tape part is to determine feature information of ribbon cassette by determining whether there is a gap at the upper and lower shells corresponding to the position of the printing device's determining column. This can avoid the problem of incapable of determination due to a slight misplacement during installation of the ribbon cassette and other problems. However, only a few switching devices are provided in the patent CN100429081C, the amount of information detected is thus less. However, with the development of ribbon cassette product, the amount of information included in the ribbon cassette is increasing, such as the width of the printing tape in the ribbon cassette; the width and the color of the medium tape; the width and the color of the carrier tape; the width of the ribbon cassette; and the printing way of printing tape (e.g., mirror printing or non-mirror printing, etc.). It is obvious that it cannot meet the requirement if a small number of the switching devices are adopted. In addition, in the case that a parallel switching device is required (see FIG. 29 for details), the aforementioned technical solution in the patent is difficult to be achieved.